Fourteen-analyser high-resolution hard X-ray emission spectrometer at I20 beamline at Diamond Light Source

We report the technical design, implementation and operation of a newly developed X-ray emission spectrometer on the I20 beamline at Diamond Light Source. The spectrometer consists of 14 crystal analysers arranged in an up-down configuration, allowing for operation in one- or two-colour acquisition modes. Since beginning operations in 2023, the spectrometer has substantially enhanced the capability of the beamline to perform X-ray emission spectroscopy (XES) and has demonstrated high reliability with minimal operational issues during user experiments. The latter achievement is particularly significant given the complexity of the instrument, and the difficulty of maintaining the Rowland condition when scanning the energy. We show that the spectrometer can effectively measure spectra in two-colour mode and is capable of detecting weak valence-to-core emission features with a significantly improved signal-to-background ratio. We also present data taken using a newly developed quick-scanning XES acquisition mode, which enables data collection in seconds rather than minutes. This mode opens up possibilities for time-resolved studies and investigating radiation-sensitive materials.